[An experimental study of hearing loss caused by mumps virus in guinea pigs]

Guinea pigs were inoculated with mumps virus into the scala tympani to establish an experimental animal model of viral labyrinthitis. Electrophysiological reactions of the inner ears were assessed by ECoG and histopathological changes of the cochleas were investigated under light and electron microscopes. Viral lesions or/and proliferation were demonstrated in 19 out of 25 cochleas. Compound action potential (CAP)N1 thresholds for the nineteen cochleas showed very significant elevations (P < 0.001) after inoculation with mumps virus. This study revealed that viral labyrinthitis caused by mumps virus presented various lesions in the stria vascularis, Reissner's membrane, basilar membrane and Corti's organ. Viral particles were found in the marginal, intermediate and capillary endothelial cells of striae vascularis. Pathological changes of the hair cells of the experimental animals were closely associated with elevations of CAP thresholds, the more serious pathological changes, the higher the CAP thresholds.